BISC314:Lab4: Difference between revisions
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Today we will be testing if any of your isolates are secreting Auto-Inducer (AI) into the surrounding media. Specifically, we will be using a strain of bacterium called ''Chromobacterium violaceum''. This organism is gram-negative and normally found in the soil. It produces a very strong purple pigment (hence the name) in response to levels of AI. We will also use a violacein-negative, mini-Tn5 mutant of ''C. violaceum'' (CV026) which can produce pigment in response to the AI from other bacteria but can no longer secrete its own AI - this will be our biosensor. <br> | Today we will be testing if any of your isolates are secreting Auto-Inducer (AI) into the surrounding media. Specifically, we will be using a strain of bacterium called ''Chromobacterium violaceum''. This organism is gram-negative and normally found in the soil. It produces a very strong purple pigment (hence the name) in response to levels of AI. We will also use a violacein-negative, mini-Tn5 mutant of ''C. violaceum'' (CV026) which can produce pigment in response to the AI from other bacteria but can no longer secrete its own AI - this will be our biosensor. <br> | ||
1. Label your agar plates. You will draw a line down the middle of the plate and write CV026 on one side and your isolate code on the other side. Also label a plate for our positive control, the parent strain to CV026: ''Chromobacterium violaceum ATCC 12472''. <br> | 1. Label your agar plates. You will draw a line down the middle of the plate and write CV026 on one side and your isolate code on the other side. Also label a plate for our positive control, the parent strain to CV026: ''Chromobacterium violaceum ATCC 12472'', also known as CV017. <br> | ||
2. Flame your loop. Use your loops to dip into an overnight culture of CV026. Streak 1/2 of an agar plate with this organism (the side with the CV026 label). <br> | 2. Flame your loop. Use your loops to dip into an overnight culture of CV026. Streak 1/2 of an agar plate with this organism (the side with the CV026 label). <br> | ||
3. Flame your loop. Grab a relatively large amount of your isolates and streak them near to the CV026 streaks. Re-flame your loop. <br> | 3. Flame your loop. Grab a relatively large amount of your isolates and streak them near to the CV026 streaks. Re-flame your loop. <br> | ||
4. Dip the loop into an overnight culture of ATCC 12472 and streak it near to the CV026 streak.<br> | 4. Dip the loop into an overnight culture of ATCC 12472 and streak it near to the CV026 streak.<br> | ||
5. Place your plates upside down till next week. If your isolates are producing AI sensed by CV026, you will see a purple pigment.<br> | 5. Place your plates upside down till next week. If your isolates are producing AI sensed by CV026, you will see a purple pigment.<br> | ||
'''Recreating your cheese rind -- isolates to community'''<br> | |||
Today we will also be attempting to recreate the rinds found on your cheese by inoculating a fresh cheese (chevre) with your isolates in combination. You can set up three different experiments and observe what the rinds look like over the next few weeks. Choose three different combinations of isolates or those from different parts of your cheese. <br> | |||
1. Label an empty petri dish with the experimental condition. <br> | |||
2. Label a 1.5 ml microcentrifuge tube with the same notation. <br> | |||
3. | |||
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